Highly effective device for wet-separation



July 5, 1960 F. WULTSCH HIGHLY EFFECTIVE DEVICE FOR WET-SEPARATION Filed March 2, 1955 v INVENTOR. 1711a ltoqiz,

Un ted Saw Patent HIGHLY EFFECTIVE DEVICE FOR WET-SEPARATION '2 Claims. (Cl. 241'42) The wood-pulpcoming from the boilers has to be decomposed before it .can be subjected to further treatment and knots, sand and foreign matter, such as splinters can be removed. This procedure is eflected in separating-devices in a way that the fibrous bundles are dissolved and fibres adhering to the boiled branches are removed. Hitherto, the separators have been agitating devices, provided with one or two stirring-shafts,mounted in a tub which either was concrete 'or pine-wood. The basin could beeither open at the top, provided the side walls were high enough, or sealed by a cover. The stirringshafts were madeiof wood and furnished with a steelshaft. Stirring was done by round fan-arms made of ash Wood, which is arranged around the wooden shaft in a helical path, while. the material was moved from the inlet to the outlet of the tub. These separators worked on V a fully dry principle, the consistency being 18-2Q%.

Theboiled wood was charged into the separating-device either by hand, by a dredging-device or by a pumping system. In order to achieve absolute dryness (18- 20%) of the transported material, the latter had to-be thickened before it was admitted into the separators.

This thickening-procedure not only required special equipment but also involved losses of fibrous material, increased consumption of power, higher costsand, accordingly, increased repairing. In separating-devicesas used hitherto not only the material, which was not yet broken had to be subjected to treatment in the separator, but also the material, which was already broken-up or dissolved respectively. Besides cellulose-particles, which were, still hard after boiling, were not. completely, dissolved, and this means, this design was inadequate for achieving perfect separation of the fibres from undissolved wood in harder cellulose-material, unless great amounts of splinters were formed. In the high-capacitywet-separator as suggested by this invention the propellershaped blades mounted in the tubular tub are exchangeable as well as adjustable and are helically arranged along the shaft in certain distances. A sieve with adjustable (lemming-plates is mounted above the bottom of the tub.

Attached drawing is a showing of a practical example: Figure I shows a longitudinal section, Figure II a topview, Fig. III a cross-section of the device, Figure 4 is an enlarged view partly in elevation and partly in cross section, showing the mounting of the propeller blades, and,

Figure 5 is an enlarged view of the means mounting the damming plate on the vat.

The tubular vat 2 is cylindrical and is divided at the center along its longitudinal axis and the vat is held together by screw connections. The upper part of the vat is solid sheet metal and isprovided on its outer wall with sight glasses 15 of Plexiglas or the like, thereby enabling the interior of the appratus to be conveniently observed. The upper part of the vat 2 also carries water inlets 10 to allow water to be introduced into the vat during operation so that a control is also possible during the disintegrating-process. V

At the end opposite to the inlet end 1, the upper part of the vat is provided with an ejecting device 11 for knots and this device incorporates a slide valve plate 17. The

2 ejecting device is attached tangentially to the end of the vat and serves for the ejection of knots or of inferior or unboiled pulp portions which must be separated from the good pulp and removed from the vat. The valve plate 17-functions to retain the knots in the apparatus for a shorter or longer time in order to expose the same to a prolonged treatment by the means to be later more fully described. r a

' The lower part of the vat 2 is provided throughout its length with replaceable perforated sieve plates 4. This arrangement permits the insertion, within a very short time, of sieves of widely different hole diameters, to suit tht particular conditions encountered. By use of the sieves, the individual fibers which have already been released from the fiber'bond will be separated from that portion of the pulp which has not yet been disintegrated and the. fibers will thenbe, removed from the vat 2 to prevent a further mechanical action on the fibers whereby the fibers may be damaged. It is a particular feature of the assembly that the perforations have a conioally milled rim portion on the outside of the sieve plates toavoid.

The plates 8 extend at right angles to the axis of the vat and are connected to the vat by screw means o'r bolts passing through openings in the flange means and perforations in the sieve. The damming plates are arranged in parallelism and can be relatively adjusted or displaced by removal of the screw means, and position ing the flange means in registry with other perforations in the. sieve, after which the screw means or bolts are manipulated to secure the plates in the adjusted po sitions thereby allowing the provisionof zones of difierent length in the tubular vat in order to retain the pulp material in the vat for a longer or shorter time and to vary the treatment time of the material to be processed. The plates 8 difier also in height, namely, in the height of the segment of a circle, to allow a good adaptation thereof to all operational requirements. The smaller the height of the segment of a circle, the shorter will be the retention time of the pulp in the vat.

As shown in Fig. 1, an essential means located inside the vat are the so-called fixed blades 7 and these blades are attached to the inner periphery of the vat 2 at an angle of degrees in four rows which are parallel tothe generatrix of thevat (Figs. I and III). The blades 7 are secured to the vat by screw means 7a in such a manner that the spacing of the blades of a row can be varied. The screw connection is such as to enable the easy replacement of the blade with a blade of difierent shape.

Each. blade includes a base plate 7b having two holes for receiving the screw means 7a attaching the blade to the vat and a plate 70 extending at right angles to the base plate, with the relative position of the two plates being variable. Depending upon the requirements and in adaptation to the qualities of the pulp, the plate which extends at right angles to the base plate can be turned through a certain angle on its longitudinal axis relative to the base plate and such plate may also be. formed with perforations or slots to improve the refining of the pulp.

As previously mentioned, the vat 2 consists of two parts and carries flanges for the reception of the fixing screws at its longitudinal sides. The two ends of the vat I are also provided with flanges, to which end plates 14 supports 13 for bearings 12' are secured by screw con-'* which are non-rotatably connected by the screws 12a to the supports 13.

Propeller-like beaters or blades 6 are mounted on the shaft 3, and each beater includes a hub 6a which encircles the shaft, and two blades 6b, which can be adjusted about their longitudinal axis. Each beater 6 is secured to the shaft 3 by means of a pin 60 passing through aligned apertures in the hub and a bore in the shaft 3. To permit the adjustment of the blades about their longitudinal axis, each blade is provided with a root end 6d mounted in a socket in the hub, and the root end may be provided with an annular groove 6e. A plurality of clamping screws or the like 6 pass through the hub, and by tightening the screws the ends engage the base of the screw, thereby locking the blade in its adjusted position. Thus, the bladesof each beater 6 may be turned through any desired angle about the longitudinal axis and this is most important for the mode of operation of the apparatus. The beaters per se are arranged on the shaft 3 with an angular spacing of 60 degrees with respect to each other as is clearly apparent in Fig. III. Due to this particular staggering of the beaters and the turning of the blades through a certain angle, a rotation of the shaft will cause the pulp material in the apparatus to be conveyed in the direction of rotation. The nature of the apparatus requires that the pulp which is admitted into the vat through the inlet 1 should move through the apparatus towards the ejecting device 11 whereas the shaft 3 isrotated in a direction to oppose the flow of the pulp. The same causes a highly turbulent flow of the pulp material in the vat serving to effect the separation of the good pulp from the knots and the disintegration of the knots into individual fibers.

In order to obtain such effect with all types of pulp, from soft qualities to very hard ones, the shaft must be rotated at different speeds and to accomplish this end,

a driving gear assembly 9 is provided. The gear assern-- bly may be infinitely variable or consist of a multi-stage shift gear. The variation of speed enables the creation of the appropriate turbulence in the vat Z'for each pulp quality and the treatment of all pulp qualities processed with an equally good disintegrating effect.

The vat 2 is surrounded by a discharge vat or tub for collecting the pulp which is discharged through'the sieves 4 and for discharging the pulp through an outlet 16. The vat 5 is afiixed to the end plates 14- by means of screw connections.

The mode of operation of the invention is as follows:

The material to be treated and which has a varying consistency enters the vat 2 through the inlet 1. The fibers which are in -a disintegrated or dissolved state are immediately discharged from the first part of the lower portion of the vat, which is provided with the sieves through the discharge vat 5. The material which has not been disintegrated is disintegrated by the beaters 6 carried by the shaft 3 and adjustable on the shaft along a helical path, in conjunction with the blades 7 on the inside of the vat. The movement of the beaters initiates a turbulent movement of the material and this action can be made more violent by the adjustable damrning plates 8. The position of the beaters 6 which positions are adjustable on the shaft 3 and the speed and direction of the rotation of the shaft also have a considerable effect on the turbulent movement of the pulp.

After the material has passed the separator, the rest of the undissolved fibers consists of inadequately boiled pieces of wood and of unboiled knots. The same are discharged through the ejection device 11, with the discharge being controlled by the slide valve plate 17.

The procedure of dissolving the wood-pulp is controlled by spraying water into the different zones and thickening of the material in the last zone is realized by removal of absorbed water as well as of-fibres; thus an effect equivalent to the effect of a' dry-separator is achieved, The flowing-speed is controlled by means of the adjustable damming-plates 8 and the slide valve plate 17; thus the period, during which the boiled wood or cellulose respectively is treated in this device, is determined as well.

The outlet 16 of the dischage vat or tub 5 can be connected with a pump, which enables this procedure to be carried out with low pressure as well.

The performance of the machine may be enhanced, i.e., the disintegration of the pulp may be increased by a preferably sudden change in the speed or direction of rotation of the beater shaft.

Experience has shown that the greatest turbulence in the separator and a complete disintegration of the pulp isv achieved ifthe direction of rotation of the beater shaft is changed intermittently and suddenly. The speed of the beater shaft is preferably adapted to the consistency of the pulp existing at any time in the separator.

The separating-device as described by this invention 7 allows a saving of 74-75% power; the percentage of power, which can be saved, depends upon the quality of the cellulose. .The losses of fibrous material could be reduced, thickening having become dispensable.

It is due to improved breaking-up of the material as well as to reduced charging of the receiver for the knots, that the receiving-device for the sand, furnished at the end of the separator as well as the receivers for the knots could be made half their former size and that cleaning of the sand-receiver could be done in half the amount of time. Thus the capacity of the separating-device can be increased by 25%.

The number of fixed blades 7 can be varied according to the quality of the material as well as to the degree to a which such material is disintegrated. Furthermore, the

sieve plates at the lower area of the tub may be replaced by plates of different gauge, and, the damrning plates 8 are exchangeable. It is further possible to adjust the amount of .water admitted in accordance with the working conditions.

What I claim is: a

1. In an apparatus for the wet separation of wood pulp, a tubular vat, a rotatable shaft extending longitudinally of the vat, a plurality of propeller-like blades on the shaft and arranged helically and adjustably on the shaft, a sieve forming the bottom ofthe tubular vat, a plurality of rigid, interchangeable beater elements within the vat and in spaced relationship to said blades on the shaft, means to vary the speed of rotation of the shaft, a plurality of adjustable damrning plates arranged in parallelism within the vat and dividing the sieve into zones, adjustable water inlets for the vat and a slide valve for controlling the outlet of tailings from the vat.

2. An apparatus for the wet separation of wood pulp comprising a tubular vat, a rotatable shaft extending longitudinally of the vat, a plurality of propeller-like blades, means mounting the blades on the shaft to extend helically thereof, including means for adjusting the blades along the longitudinal axis, a sieve forming the bottom of the tubular vat, a plurality of rigid, interchangeable beater elements within the vat and in spaced relationship to said blades on the shaft, means for driving the shaft at variable speeds, a plurality of adjustable damrning plates arranged in parallelism within the vat extending transversely of the axis of the shaft and dividing the sieve into zones, water inlets associated with at least some of the zones, pulp inlet means at one end of the vat, a tailings outlet at the other end of the vat, and a slide valve for controlling the discharge through tailings outlet means.

References Cited in the file of this patent UNITED STATES PATENTS 592,090 Harrell Oct. 19, 1897 724,100 Henius Mar. 31, 1903 811,930 Kihlgren Feb. 6, 1906 2,752,828 Sandison July 3, 1956 

